Lawmakers and scientists sharply contest the issue of climate change. Arguably, the need for climate change laws extends beyond the controversy of whether the climate is changing and what potential affect that might have on the environment. These laws are also intended to mitigate damage from pollution, encourage sustainability, and prevent visible environmental degradation. However, with various economic and political issues at stake, lawmakers must surmount opposition in order to pass laws that ease the effects of climate change on the environment. Science is the most powerful method that convinces leaders and their constituents that binding laws designed to abate climate change are necessary. In 2009, the application of science deeply affected the current state of climate change laws, both in the United States and internationally.

In the United States, the biggest news from the Environmental Protection Agency regarding its interpretation of scientific evidence was its decision to regulate carbon dioxide as a greenhouse gas. In April, the E.P.A. reversed its previous position that it could not regulate carbon dioxide because the gas was not a pollutant. The E.P.A. announced the policy change following the 2007 mandate from the Supreme Court requiring it to again review scientific evidence on climate change. The agency makes its scientific determinations from the assessments of United States agencies, as well as the Intergovernmental Panel on Climate Change. The I.P.C.C.’s most recent comprehensive scientific release, 2007’s Fourth Assessment Report, observed that, “Warming of the climate is unequivocal,” and is very likely due to an increase in greenhouse gases, which include carbon dioxide.

In November, the public questioned the integrity of climate change science in general when the computer systems at the University of East Anglia’s Climatic Research Unit were hacked. The hackers posted e-mails sent between various British climatologists online. Global warming skeptics quickly asserted that the released statements could be construed to imply that the scientists falsified or skewed data to overstate the urgency of their findings. Several of the authors confirmed they wrote the e-mails but defended that their data were properly attained and proved that the climate is warming. As a result of these events, climate skeptics were able to cast some doubt on the veracity of climate change science upon which lawmakers rely.

Shortly after the e-mail scandal subsided, the leaders of many nations met in Copenhagen in an attempt to reach an international agreement to manage climate change issues. The summit was part of the United Nations Framework Convention on Climate Change, the treaty designed to consider how to reduce and cope with its effects. The U.N.F.C.C.C., similarly to the E.P.A., relies on the findings of the I.P.C.C. that warming of the climate is unequivocal, and due to greenhouse gases. However, the representatives in Copenhagen were equally concerned with politics as they were with scientific evidence. The interests of the nations in attendance were highly divided. The largest contributors to greenhouse gas emissions were prepared to make reductions immediately, but only with the same commitment from the global community. In particular, the United States wanted China to agree to international monitoring of its emissions. Meanwhile, emerging developing countries, such as China and India, were hesitant to stifle their own economies to resolve a problem they did not create. This deep divide made it impossible for nations to create a binding world treaty. Instead, the summit ended with the Copenhagen Accord, a document urging nations to achieve certain emission targets. Under the accord, the United States promised to raise billions of dollars to aid other countries, while also agreeing to lower emissions here. However, with the targets not yet incorporated into the accord and the limited enforceability of the international agreement, the Copenhagen Accord is largely considered ineffective by environmentalists.

Politics aside, the science of climate change is carefully monitored in the international arena. The United Nations maintains the annual Climate Change Science Compendium, most recently published in October, 2009. The compendium is useful for providing background information on climate change as well as recent updates. Some of the current information includes an analysis of extreme weather events, a study involving components of the earth’s system that are vulnerable to more abrupt climate change, and new suggestions for interventions that government agencies could use to facilitate ecosystem adaptation to climate change.

In 2010, the state of knowledge of climate change science is bound to evolve. The I.P.C.C. has already begun preparations for its Fifth Assessment Report, scheduled to be completed in 2014. The E.P.A. and industries affected by new United States carbon dioxide regulations will continue to monitor exactly how the gases effect climate change and how new technologies can help curb emissions. Most importantly, lawmakers will continue to struggle with the conflicts between scientific evidence and politics in order to make nationally and internationally binding laws.